Hyaluronate metabolism has been correlated with morphogenetic sequences during development. The major aim of the projects is to investigate the role of hyaluronate in morphogenesis. In order to approach this aim we are studying the nature of association by hyaluronate with the surface of mesenchymal cells, the mechanisms of hyaluronate synthesis and of hyaluronidase action and the mode of influence of hyaluronate on various aspects of cell behavior. BIBLIOGRAPHIC REFERENCES: Linsenmayer, T.F. and Toole, B.P.: Biosynthesis of different collagens and glycosaminoglycans during limb development. In: 'Morphogenesis and Malformations of Limb', ed. D. Bergsma, National Foundation-March of Dimes, in press, 1977. Toole, B. P. and Linsenmayer, T.F.: Newer knowledge of skeletogenesis: Macromolecular transitions in the extracellular matrix. Clin. Orthopaed. Rel. Res., in press, 1977.